Abstract:Significance Tungsten(W)-based composite powders play a crucial role in various high-tech fields such as aerospace,nuclear energy,and microelectronics due to tungsten's excellent properties,including high melting point,high density,and good ther-mal conductivity.This review aims to comprehensively summarize the research status of the preparation technologies of W-based composite powders and analyze their characteristics and existing problems,thereby providing a reference for the development of high-performance W-based materials. Progress In the preparation of second-phase particle-doped W-based composite powders for fusion devices,mechanical ball milling is commonly employed.However,mechanical ball milling has certain drawbacks.Prolonged high-energy milling can lead to wear of the milling jar liner and balls,resulting in contamination of the composite powders.Moreover,extended milling time increases the surface energy of the powders,which accelerates sintering neck formation and excessive grain growth during sintering.Chemical methods for preparing second-phase particle-doped W-based composite powders mainly include solid-liquid doping and liquid-liquid doping.Solid-liquid doping is typically applied in carbide dispersion strengthened(CDS)W materials but faces challenges due to the reaction between carbides with oxygen during sintering.In contrast,liquid-liquid dop-ing is commonly used for oxide dispersion-strengthened(ODS)W materials.In recent years,various chemical methods have been developed,such as wet chemical methods,sol-gel processes,freeze-drying,and hydrothermal methods.Although these chemical methods can produce ODS-W-based composite powders with excellent microstructures,environmental concerns regard-ing ammonia and nitrogen oxides must be addressed in large-scale production.For W-rhenium(Re)alloy powders designed for high-end equipment,the primary goal is to achieve a uniform solid solution distribution of W and Re.Mechanical methods still struggle with uneven alloying.Mixed methods,including solid-solid and solid-liquid doping,are widely used.Among these,solid-liquid doping can achieve better dispersion and more uniform distribution of W and Re compared to solid-solid doping.However,for W powders with high Re content,uniformity remains insufficient.Chemical methods using ammonium metatung-state and ammonium perrhenate as raw materials,in combination with processes such as co-precipitation,sol-gel,and spray drying,are gradually emerging as new approaches to prepare uniform,ultrafine W-Re alloy powders.However,due to the dif-fering reduction characteristics of W and Re powders,issues of compositional uniformity persist.In the preparation of W-copper(Cu)composite powders,both mechanical and chemical methods are employed to enhance the sintering activity.However,mechanical alloying often leads to severe powder agglomeration and introduces impurities such as manganese and iron,adversely affecting the conductivity and thermal conductivity of W-Cu composites.Chemical methods,including electroless plating,sol-gel processes,co-precipitation,and wet chemical methods,can effectively improve sintering activity.Subsequent studies have shown that the addition of silver can enhance the density and performance of W-Cu composites.Overall,each method for prepar-ing W-based composite powders has their advantages and disadvantages. Conclusions and Prospects In summary,current preparation methods for W-based composite powders exhibit distinct advan-tages and disadvantages.Future research should focus on optimizing preparation processes to enhance powder quality and perfor-mance.For second-phase particle-doped W-based composite powders,the exploration of more environmentally friendly chemi-cal methods and better control over second-phase particle distribution is essential.For W-Re alloy powders,addressing compo-nent uniformity,particularly in high-Re content powders,is crucial.In the preparation of W-Cu composite powders,efforts should be directed toward improving plating quality in chemical methods and minimizing impurities in mechanical methods.With the continuous development of related industries,the demand for high-performance W-based materials is expected to grow,indicating broad prospects for research in W-based composite powder preparation technologies.

Abstract:Significance Plastics are widely used across various sectors,including food packaging,textiles,construction,and healthcare,owing to their cost-effectiveness,lightweight properties,and remarkable chemical stability.However,due to their slow degrada-tion rates,plastics tend to accumulate on land or be transported into the ocean,posing severe environmental threats.Traditional plastic waste disposal methods,primarily landfilling and incineration,are criticized for occupying vast land areas and emitting toxic gases.In comparison,plastic recycling offers a more sustainable approach by breaking down waste plastics into monomers and converting them into high-value chemicals,supporting the circular economy.Among plastics,polyethylene terephthalate(PET),a polyester synthesized from terephthalic acid(TPA)and ethylene glycol(EG),stands out for its thermal stability,transparency,and lightweight properties,making it ideal for beverage bottles and textiles.However,PET recycling rates fall far behind their production rates.Moreover,existing PET recycling methods are mostly energy-intensive and prone to generate sec-ondary pollutants,toxic byproducts,and harmful gases.Pyrolysis-based PET recycling further exacerbates these issues by pro-ducing formaldehyde,greenhouse gases,and polycyclic aromatic hydrocarbons.These byproducts reduce thermal energy utiliza-tion efficiency and intensify the greenhouse effect,posing further risks to the ecological environment and human health. Progress This article focuses on chemical recycling methods for PET,with particular emphasis on techniques such as glycoly-sis,alcoholysis,and hydrolysis.The reaction mechanisms and catalysts used in each method are systematically elucidated,and the latest advancements in glycolysis and hydrolysis methods are summarized.In addition,this article explores bioremediation approaches for PET recycling,examining the reaction activity and underlying mechanism of enzyme-catalyzed PET hydrolysis under mild conditions.Key enzymes such as keratinase and PETase are discussed as examples,and cutting-edge technologies in enzyme-catalyzed PET recycling are introduced.The biological recycling of PET offers the following advantages.It operates under mild reaction conditions,without the need for high temperatures and pressures or additional alcohol/acid-base reagents.The degradation products can be transformed into high-value chemicals.Compared to chemical recycling,biological recycling not only reduces costs but also minimizes secondary environmental pollution.These benefits show its broad application prospects and significant research value. Conclusions and Prospects The development of green PET recycling technologies has become an urgent priority due to their sig-nificance for environmental protection and sustainable development.Both chemical and biochemical PET degradation methods offer significant advantages,including energy efficiency,environmental friendliness,and the ability to convert waste into mono-mers as chemical raw materials for secondary utilization.Therefore,chemical and biological recycling are promising research directions in sustainable materials management.Future studies on catalytic PET recycling and upgrading should focus on opti-mizing catalytic systems,elucidating reaction mechanisms,developing efficient reaction processes under mild conditions,and enhancing product value and applications.Moreover,technical and economic analyses and life cycle assessments should be inte-grated throughout the entire research process to comprehensively evaluate the feasibility and sustainability of new catalytic sys-tems,thereby ensuring their economic viability and environmental friendliness in practical applications.

Abstract:Objective This study investigates the surface wear on selective catalytic reduction(SCR)catalysts in cement kilns under various conditions to determine optimized solutions for reducing wear.It aims to identify key factors affecting catalyst surface wear and proposes optimized measures to reduce wear and extend the catalyst's service life. Methods A coupled approach using computational fluid dynamics(CFD)and the discrete element method(DEM)was applied to simulate wear on the cement kiln SCR catalyst surface.The accuracy of the numerical simulation model was validated using experimental data to ensure that the model could accurately reflect actual operating conditions.After validation,simulations were conducted to investigate the effects of different inlet velocities,incidence angles,and particle sizes on catalyst surface wear.The study analyzed the flow characteristics and impact mechanisms of particles at various inlet velocities and explored how changes in incidence angles affected wear distribution patterns.Additionally,the study investigated the movement trajectories of particles with different sizes and their impact on the amount and uniformity of wear distribution. Results and Discussion As inlet velocity increased,both the average initial wear and the mean steady-state wear on the catalyst surface increased due to the higher kinetic energy generated from the impacting particles.Larger incidence angles reduced the contact area between particles and the surface,leading to decreased wear.Smaller particles resulted in lower average wear and standard deviation with a more uniform wear distribution,extending the catalyst's service life.The experimental data showed that at inlet velocities of 2,3,4,and 5 m/s,the mean wear on the catalyst surface stabilized at 1.12×10-7,1.32×10-7,2.52× 10-7,and 3.78×10-7 mm,respectively.Appro×imately 10 seconds later,the standard deviation of wear peaked,suggesting that the wear pattern stabilized at this point.At inlet velocities of 2,3,4,and 5 m/s,the ma×imum standard deviation values were 1.82×10-8,2.41×10-8,2.46×10-8,and 2.52×10-8 mm,respectively.This findings indicated that higher velocities caused greater wear and variability in wear distribution,likely due to the complex dynamic processes of high-velocity particle impacting on catalyst surface. Conclusion The standard deviation of wear on the catalyst surface initially increases and then decreases over time,indicating high variability in the early stages of wear,possibly due to random particle impacts.However,as the system gradually stabi-lizes,wear variability decreases.Similarly,the maximum wear amount initially increases and then declines,likely due to the chaotic movement of particles generating significant impact energy in the early stages.Then as the system stabilizes,the move-ment also subsides.Furthermore,the study reveals that smaller particles tend to cause more variability in surface wear,while larger particles have a more pronounced impact on the maximum wear.These findings are crucial for understanding catalyst sur-face wear mechanisms and provide valuable insights for catalyst material selection and operational strategies to mitigate wear in practical applications.

Abstract:Significance Nanomaterials,with their distinctive physical and chemical properties,are the foundation for new energy technolo-gies.Among these,photothermal catalysis and electrocatalysis are the major contributors to the advancements in energy conver-sion,storage,and environmental sustainability.Nanomaterials,with their tunable properties and enhanced surface-to-volume ratios,are particularly suited for these applications.Laser technology,a cutting-edge method for synthesis and micro-nano pro-cessing,has demonstrated unparalleled advantages in precise nanomaterial fabrication and intricate nanostructure construction.It offers high precision,flexibility,and scalability,making it an invaluable tool in nanotechnology.Despite the remarkable pro-gresses in laser-assisted nanomaterial synthesis,the complex dynamics of laser-material interactions and the underlying mecha-nisms of laser-induced synthesis remain largely unexplored.A deeper understanding of these phenomena is crucial for further optimizing synthesis processes,enhancing material quality,and tailoring properties for specific applications.Therefore,contin-ued research into these fundamental aspects is essential for harnessing the full potential of laser technology in nanomaterial fabrication. Progress The regulation of laser-induced thermal and plasma effects is pivotal for shaping the structure and functionality of nanomaterials.Intense heat generated from laser pulses facilitates the synthesis of carbon materials and carbides,which are often difficult to form under ambient conditions due to their high energy requirements.Rapid thermal cycles induced by laser pulses disrupt the crystal structure of metal oxides,creating oxygen vacancies that serve as unique anchoring sites for precious metals,therefore enhancing their catalytic activity.Laser-induced plasma effects enable the rapid ionization of metals,leading to the formation of alloy structures and single-atom alloys.These structures often exhibit superior catalytic properties due to their optimized electronic configurations and enhanced surface areas.By manipulating the atmospheric conditions during laser synthe-sis,various metal sulfides,nitrides,carbides,and borides can be synthesized,each with unique physical and chemical proper-ties tailored for specific applications.The micro-nano structures constructed through laser processing can significantly improve light absorption,affecting metal-carrier interactions and enhancing photothermal catalytic activity.In aquatic hydrogen elec-trolysis,laser technology can effectively reduce the adsorption energy of hydrogen on catalyst surfaces,accelerating hydrogen desorption and enhancing the electrolysis efficiency.In electrocatalytic nitrogen reduction,laser treatment can adjust the hybrid orbit of metal carbides,promoting nitrogen adsorption and increasing ammonia yields.With laser-controlled core-shell struc-tures and alloy strategies,hydrogen production sites can be introduced to accelerate the efficiency of electrocatalytic nitric acid reduction.In electrocatalytic carbon dioxide reduction,laser processing can construct metal oxide series catalytic sites that favor the formation of valuable intermediates like formic acid in the synthesis of fuels and chemicals. Conclusions and Prospects The interactions between laser and matter generate localized light,thermal,pressure,and plasma fields,enabling the construction of micro-nano structures,defect formations,and alloyed structures.These capabilities have revolutionized the development of energy storage and conversion electrode materials.Significant progress has been made in developing high-performance electrode materials tailored for specific energy applications.Future research will focus on the corre-lation between laser technology and material properties.By leveraging the controlled preparation and adjustment advantages of laser technology,specific catalytic structures with high catalytic activity can be designed and synthesized.High-energy lasers,effective monitoring,and a clearer understanding of the underlying mechanisms are the key areas of focus for future research.Integrating laser continuous synthesis with continuous feeding systems is expected achieve large-scale industrial application of new energy catalytic nanomaterials.Moreover,the development of advanced laser systems with higher precision,shorter pulse durations,and broader tunability will further expand the scope of laser-based nanomaterials synthesis.The combination of machine learning and artificial intelligence with laser processing techniques could optimize synthesis parameters,predict mate-rial properties,and accelerate the discovery of new nanomaterials with exceptional performance.In conclusion,laser-based nanomaterials synthesis holds vast potential in energy conversion,storage,and environmental sustainability.By unraveling the complexities of laser-material interactions and the mechanisms underlying laser-induced synthesis,the field will revolutionize the way we harness and convert energy,paving the way for a cleaner,more sustainable future.

Abstract:Objective With the advancement of powder processing technology,polyvinyl chloride(PVC)powder has been widely used as a synthetic material in various fields such as plastic products,building materials,pipes,and cables.However,the electrostatic buildup risk during powder processing has gradually become apparent.During the production,transportation,processing,and storage of PVC powder,friction and collisions between particles,as well as between particles and pipelines,equipment,and containers,lead to the accumulation of electrostatic charge.When the accumulated charge reaches a certain level,electrostatic discharge can occur,potentially igniting the powder and causing fires or explosions,resulting in casualties and property damage to enterprises.The study aims to explore the impact of moisture content,feeding rate,and conveying speed on the electrostatic charge quantity in PVC powder during pneumatic conveying and to reduce the generation of electrostatic charge and the risk of electrostatic discharge. Methods In this study,a self-built pneumatic conveying platform was used to conduct experimental research on PVC powder with different moisture contents under varying feeding and conveying speeds.First,2 kg of PVC powder was taken,and the moisture content(d)was adjusted by changing the mass ratio of water to PVC powder.Five groups of samples with moisture con-tents of 0％,1％,2％,3％,and 4％were prepared,labeled as SO,S1,S2,S3,and S4,respectively.After sample prepara-tion,the effect of moisture content on the charge-to-mass ratio at different feeding rates was investigated.Based on the recom-mended conveying speed for PVC powder in pneumatic conveying,a conveying speed of 9.1 m/s was selected.The 2 kg of PVC powder was then fed over durations ranging from 1 to 5 minutes.After the conveying experiments,samples were taken from the ash bunker and placed in a Faraday cup to measure the electrostatic charge.The mass of the samples was also measured,and the charge-to-mass ratio of the PVC samples was calculated.Based on the results of the previous experiments,an optimal feed-ing rate of 6.7 g/s was selected as the fixed parameter for this set of experiments.The conveying speed was then adjusted by changing the speed of the induced draft fan,with five different conveying speeds of 7.9,9.1,10.3,11.2,and 14.8 m/s,to investigate the effect of moisture content on the charge-to-mass ratio at different conveying speeds. Results and Discussion When the moisture content of the PVC powder was constant,the charge-to-mass ratio decreased with an increase in feeding rate and increased with an increase in conveying speed.When the feeding rate increased from 6.7 g/s to 33.3 g/s,the charge-to-mass ratio decreased the most for powder with 0％moisture content,from 14.581 μC/kg to 7.325 μC/kg.However,when the moisture content was 3％,the feeding rate had little effect on the charge-to-mass ratio.When the conveying speed increased from 7.9 m/s to 14.8 m/s,the charge-to-mass ratio increased the most for powder with 0％mois-ture content,from 5.435 μC/kg to 34.891 μC/kg.However,when the moisture content was 2％,the conveying speed had little effect on the charge-to-mass ratio.At the same feeding rate,the higher the moisture content of the PVC powder,the lower the charge-to-mass ratio.When the feeding rate was 6.7 g/s,the charge-to-mass ratio changed the most with moisture content,decreasing from 14.581 μC/kg to 0.008 μC/kg as the moisture content increased from 0％to 4％.However,when the moisture content increased from 3％to 4％,the charge-to-mass ratio decreased by only 0.029 μC/kg,indicating that further increases in moisture content beyond 3％had little effect on the charge-to-mass ratio.At the same conveying speed,the higher the moisture content of the PVC powder,the lower the charge-to-mass ratio.When the conveying speed was 14.8 m/s,the charge-to-mass ratio changed the most with moisture content,decreasing from 34.891 μC/kg to 0.212 μC/kg as the moisture content increased from 0％to 2％.However,when the moisture content increased to 3％,the conveying pipeline became blocked during the pneu-matic conveying experiments.Based on the charge-to-mass ratio at different conveying speeds for PVC powder with 2％moisture content,it was found that a moisture content of 2％was sufficient to meet engineering application requirements. Conclusion During pneumatic conveying,appropriately increasing the moisture content of PVC powder,increasing the feeding rate,and reducing the conveying speed can effectively suppress the accumulation of electrostatic charge and reduce the risk of electrostatic hazards.However,the moisture content should not be excessively increased,as too much moisture can easily cause pipeline blockages.When the moisture content of PVC powder is 2％,it can meet the engineering application requirements of ensuring smooth production while reducing electrostatic charge accumulation.

Abstract:Objective This study investigates the property changes in recycled concrete aggregates(RCA)before and after carbonation treat-ment,focusing on the reinforcement mechanisms that carbonation exerts on both macro-properties and microstructural character-istics through multi-scale analysis.The correlation between carbonation processes and property enhancement in RCAs was estab-lished for the first time,aiming to enhance the resource utilization efficiency of construction waste while contributing to carbon sequestration and emission reduction.The findings provide valuable theoretical support for advancing low-carbon recycling tech-nologies in the construction sector,aligning with the"carbon peak and carbon neutrality"goals. Methods In this study,RCA were crushed and sieved into three categories of particle size(5～10 mm,10～20 mm,and 20～26 mm).The aggregates underwent pre-wetting treatments of 0,1,12,and 24 hours before being subjected to carbonation under controlled conditions(20％CO2 concentration and 0.4 MPa pressure)for 6 hours.The effect of pre-wetting duration on carbonation efficiency was analyzed,and further investigations were conducted based on the identified optimal pre-wetting dura-tion(1 hour)to examine the variations in mass growth rate for the three particle sizes after carbonation durations of 6,12,and 24 hours.A comparative analysis was performed to evaluate the effects of different carbonation durations on key physical proper-ties,including apparent density,water absorption,crushing value,and microstructural characteristics of the aggregates. Results and Discussion The carbonation treatment showed optimal properties after a 1-hour pre-wetting,with the 5～10 mm fraction demonstrating enhanced reinforcement due to its higher specific surface area.Under the controlled carbonation condi-tions(20％CO2 concentration and 0.4 MPa pressure),the 5～10 mm aggregates exhibited a 3.34％increase in apparent density(2.430～2.512 g·cm-3),a 28.42％reduction in water absorption(4.12％～2.95％),and a 13.36％decrease in crushing value(18.7％～16.2％)after 6 hours of carbonation.The CaCO3 mass loss was 18.16％,which was attributed to the crystalline phase transformation detected through XRD analysis and corresponded to a carbon sequestration efficiency of 41.27％,approximately 2.29 times higher than the non-carbonated control group(12.57％).In contrast,the large aggregates(20～26 mm)displayed a carbon sequestration efficiency of only 32.02％,which was 22.41％lower than the smaller aggregates.This size-dependent dif-ference originated from variations in CO2 diffusion kinetics,where the smaller aggregates,with their shorter gas transport paths,allowed for more complete carbonation reactions. Conclusion Carbonation treatment results in the formation of dense calcium carbonate crystals on the surface of RCA,filling the pores within the aggregates,thereby increasing apparent density and reducing both water absorption rate and crushing value.Factors such as pre-wetting duration,carbonation time,and particle size significantly affect the carbonation efficiency.A shorter pre-wetting duration and longer carbonation time lead to optimal properties in smaller particle size aggregates.

Abstract:Objective This study systematically investigates the damage mechanisms of diamond-silicon carbide(SiC)composites during femtosecond laser cutting with a focus on how laser power affects surface morphology,roughness,and crystallographic structure.By correlating laser parameters with the material response,the study aims to offer theoretical insights for optimizing processing conditions,thereby balancing cutting efficiency and surface quality in ultrahard composites. Methods Diamond-SiC composites were synthesized via silicon vapor infiltration(SVI).A porous diamond preform with an average particle size of 50 μm,was infiltrated with silicon vapor at 1 600 ℃ under vacuum,resulting in a dense composite with a final density of 3.05 g/cm3.Specimens were polished to a surface roughness(Ra)≤1 μm before laser processing.Femtosecond laser cutting was performed under four power levels(0 W,2 800 W,3 000 W,3 200 W)with fixed parameters:a wavelength of 1 064 nm,repetition frequency of 3 kHz,pulse width of 30 μs,and scanning speed of 50 mm/min.For post-processing char-acterization,X-ray diffraction(XRD)was employed for phase analysis,scanning electron microscopy(SEM)was utilized for surface morphology evaluation,and atomic force microscopy(AFM)was applied for 3D roughness quantification. Results and Discussion The initial surface roughness(Ra)of unprocessed samples was measured as 52.9 nm.At 2 800 W laser power,Ra slightly decreased to 49.4 nm due to localized laser-induced smoothing effects.However,when the power exceeded 3 000 W,Ra surged to 122 nm(3 000 W)and 375 nm(3 200 W),which was attributed to intensified melting,sput-tering,and thermal stress-induced irregularities.AFM analysis revealed the formation of wave-like textures and deep grooves on surfaces processed at higher powers,confirming severe surface degradation.XRD analysis identified diamond(C),SiC,silicon(Si),and graphite(GCB).Unprocessed samples showed dominant peaks corresponding to diamond(111,220)and SiC(002,111,200).At 2 800 W,minor graphite peaks emerged,indicating partial diamond-to-graphite transformation(sp3→sp2).At 3 000 W,graphite content increased significantly,accompanied by weakening SiC diffraction intensities.At 3 200 W,graphite became the dominant phase while certain SiC peaks disappeared,suggesting phase decomposition or amorphization.SEM images of unprocessed surfaces displayed uniform microtextures.At 2 800 W,fine grooves and localized melting were observed.At 3 000 W,melt pools expanded,and irregular trenches formed.At 3 200 W,extensive sputtering and non-uniform material removal resulted in chaotic surface structures.AFM further highlighted re-solidified molten regions with blurred grain boundar-ies that correlated with increased roughness.Low-power cutting(≤2 800 W)achieved"cold processing"via confined energy deposition,minimizing thermal diffusion.In contrast,high-power cutting(＞3 000 W)induced significant thermal mismatch between diamond(thermal conductivity of 2 000 W/(m·K))and SiC(490 W/(m·K)),generating interfacial stresses that pro-moted delamination.Excessive heat accumulation also accelerated diamond graphitization and SiC decomposition,ultimately degrading the material's mechanical and thermal properties. Conclusion The surface quality and structural integrity in diamond-SiC composites are controlled by laser power levels.Opti-mal surface smoothing is achieved at 2 800 W(Ra=49.4 nm),while higher powers exceeding 3 000 W lead to significantly increased roughness(Raa＞120 nm)due to thermal damage mechanisms.Phase transformations,particularly diamond graphitiza-tion and SiC decomposition,intensify with increasing power,fundamentally altering material functionality.These findings high-light the delicate balance required in laser processing parameters,and the trade-off between cutting efficiency and surface preci-sion is influenced by the interplay between thermal stress,phase dynamics,and gas-assisted melt removal.

Abstract:Significance The dual-carbon goals have spurred a significant shift in the industry,accelerating transformation and imposing higher requirements on lithium battery technologies.Driven by innovations in downstream applications,the demand for lithium batteries with higher energy density and enhanced safety has increased.Traditional liquid batteries utilizing flammable organic electrolytes are susceptible to thermal runaway,which may trigger chain reactions leading to battery pack failure and increased fire risks.Consequently,solid-state battery technology has emerged as an innovative solution,garnering growing research atten-tion.By replacing flammable liquid electrolytes with solid-state alternatives,these batteries inherently mitigate the risks of fire and explosion while significantly improving safety performance.Moreover,solid-state batteries effectively suppress dendrite for-mation,thereby substantially enhancing energy density,stability,and reliability.Despite significant progress in developing highly conductive solid-state electrolytes,most all-solid-state batteries still suffer from constrained rate performance,primarily attributed to the interfacial impedance at the solid-state electrolyte-electrode interface.However,the precise mechanisms gov-erning this impedance remain experimentally elusive.Optimizing the solid electrolyte-powder electrode interface continues to be one of the pivotal challenges in propelling its commercialization. Progress In recent years,significant breakthroughs have been made in solid-state electrolyte-electrode interface research,with the focus evolving from basic theoretical exploration to addressing key scientific challenges.Based on fundamental principles,three interface types were investigated theoretically.The inherent causes for poor interfacial contact,stability issues,and impeded ionic conduction were analyzed.Moreover,the intrinsic connection between interfacial contact resistance,electro-chemical stability,and ionic transport kinetics was systematically elucidated,thereby laying a solid foundation for interfacial optimization.Methodologically,advanced simulation techniques have emerged as powerful tools for investigating interfacial phe-nomena and predicting material behaviors.Phase-field simulations were used to model both interfacial layer formation and elec-trolyte microstructure evolution.Finite element analysis was used to quantitatively characterize the interface thermal behavior and stress distribution.This combined approach provides multidimensional insights into the anisotropic characteristics of lithium dendrite growth.In addition,finite element simulation was used to model battery aging processes during solid-state battery development.First-principles calculations haven proven particularly valuable for studying interfacial charge transfer mecha-nisms and reaction kinetics,while density functional theory(DFT)provided an efficient approach to predicting the electrode-electrolyte interfacial reactions.Nevertheless,limitations persist in accurately simulating dynamic contact behaviors at complex powder/porous-electrolyte interfaces.To address these interfacial challenges,several innovative strategies were proposed.The introduction of transition interlayers reduced interface resistance and enhanced cycle stability by increasing interfacial contact.Structural optimization strategies,particularly through sandwich configurations and three-dimensional architectures,have emerged as a promising research direction for enhancing interfacial contact.Furthermore,interfacial engineering through buffer layer design and stabilizer incorporation enhanced electrolyte-electrode interface contact,thereby improving solid-state battery performance.Additionally,a comprehensive understanding of charge behaviors under electric fields is considered crucial for achieving stable interfaces. Conclusions and Prospects Despite the progress achieved in solid-state lithium battery technology,several critical challenges must be overcome to realize its widespread adoption in energy storage systems.These challenges are intricate and multifaceted,with interfacial phenomena representing a particularly complex aspect that requires comprehensive consideration during design and optimization.Both chemical-electrochemical and physical factors must be taken into account,with special emphasis on understanding the physical interface through detailed analysis and refinement of cell internal architecture.Although simulation techniques provide theoretical support for interface optimization,their practical implementation still faces significant limita-tions.In addition,the development of advanced characterization techniques is essential for clarifying the correlations between electrochemical performance degradation and the electrode-electrolyte interface.These techniques can shed light on the micro-scopic changes at the interface and thus provide a scientific basis for improving the interfacial performance.

Abstract:Significance The fuel elements used in pebble-bed high-temperature gas-cooled reactors(PB-HTRs)are graphite spheres con-taining thousands of Tri-structural isotropic(TRISO)coated particles,which are fabricated through quasi-isostatic pressing.The coating layer of the coated particles serves as the first barrier to guarantee reactor safety.Before fuel element compression,a compression buffer layer,composed of the same material as the matrix,is wrapped around the surface of the coated particles.This layer directly and effectively mitigates damage to the coating layer during the element production process,a step known as the overcoating process. Progress China's high-temperature gas-cooled reactors(HTRs)have evolved over more than four decades,from the 10 MW high-temperature gas-cooled reactor-test module(HTR-10)to the 200 MW high-temperature gas-cooled reactor pebble-bed module(HTR-PM).Correspondingly,overcoating technologies,a crucial part of nuclear fuel production,have progressed through multiple stages:basic research-level,laboratory-scale,pilot-scale,commercial demonstration,and commercializa-tion.In terms of equipment structure,various types of overcoating equipment have been developed,including laboratory-scale onion-shaped and truncated-cone-shaped types,a meshed drum-type for commercial demonstration,and non-porous-drum and planetary types for large-scale commercial applications.The single-batch capacity has increased significantly,from 1 kgU to tens of kilograms.Meanwhile,the automation level,safety,and environmental friendliness of the equipment have been progres-sively improved while ensuring high product yield and quality.Advanced research methods,such as online analysis of particle shape and size,and numerical simulation,are used in equipment design,development,and process optimization,effectively accelerating progress and enhancing the effectiveness of research and development.So far,China's nuclear fuel overcoating technology has surpassed its international counterparts in productivity,product quality,and equipment automation and advance-ment through decades of dedicated efforts by several generations of R&D personnel. Conclusions and Prospects The evolution and advancement of nuclear fuel preparation technology,along with the scientific challenges in engineering,will garner increasing attention and attract professionals from diverse research domains into this field.Disciplines and research fields,including materials science,particle kinetic theory,fluid mechanics,and numerical simula-tion,will converge and give rise to new interdisciplinary directions in the study of the overcoating process.Theoretical achieve-ments will also lead to novel engineering concepts,promoting innovation and upgrading of overcoating equipment.With the widespread adoption of computer technology,advancements in image technology,enhanced precision and capabilities of detec-tion instruments,and ongoing process refinement and optimization,process control technology will be extensively applied to the overcoating process.This will significantly enhance the automation level of overcoating equipment.Artificial intelligence(AI)is also set to be deeply integrated into the industrial production of overcoating particles.By combining human expertise and the computer's analytical capabilities,AI will facilitate decision-making and task execution through big data analysis.The immedi-ate result of incorporating AI lies in the optimization of process parameters,thereby achieving optimal product quality and stabil-ity.With intensified theoretical research,improved automation,and the integration of artificial intelligence,overcoating tech-nology will undergo multidimensional technological transformations and evolve towards a more efficient,automated,and intelli-gent direction.TRISO-coated particles have played a pivotal role in ensuring the inherent safety of HTRs,making their structure highly favored for various types of nuclear reactors.With the rapid development of HTRs and increasing safety demands for reac-tors,the demand for accident-tolerant nuclear fuel incorporating TRISO particles will surge substantially.Consequently,over-coating technology is poised to have broader application prospects.

Abstract:Objective Spray drying technology offers the advantage of one-step formation,enabling the efficient preparation of functional microparticles.It is widely used in the food,chemical,and pharmaceutical industries.However,during the drying process,solvent evaporation within droplets causes solute migration and rearrangement,resulting in dried microparticles with complex surface structures and surface compositions that are difficult to quantify.Furthermore,the morphology,size,and crystal forms of the microparticles can all influence their performance.In this study,inverse gas chromatography(IGC)was employed to char-acterize the surface properties of the microparticles,exploring the relationship between surface composition and surface energet-ics,and further analyzing the flowability of the microparticles.The study focuses on elucidating the structure-property relation-ship between surface composition and particle performance,providing guidance for the design of functional microparticles and enabling precise control of their flowability. Methods Mannitol and sodium stearate were used as model substances.The feed liquid for spray drying was prepared using high-shear stirring,ultrasonic treatment,and microfluidic homogenization.A series of mannitol-sodium stearate microparticles was then prepared via spray drying at an inlet temperature of 120℃.The particle morphology was characterized using scanning electron microscopy(SEM),particle size was measured by laser diffraction,crystal form was analyzed using X-ray diffraction(XRD),and the chemical state of carbon on particle surfaces was examined using X-ray photoelectron spectroscopy(XPS).The surface properties of the microparticles were characterized using IGC at infinite dilution conditions:n-heptane,n-octane,and n-nonane were used to measure the dispersive surface energy;iso-octane was used to determine the surface roughness at the molecular level;and ethyl acetate and isopropanol were used to measure the surface reaction energy.In addition,the flowability of the samples was evaluated by measuring bulk density(Carr's index). Results and Discussion After spray drying,the resulting microparticles all exhibited a spherical morphology,and their dispers-ibility improved slightly with increasing sodium stearate content.However,the sodium stearate content had no significant effect on particle morphology or size.XRD results revealed that the addition of sodium stearate disrupted the formation of mannitol's ordered crystalline structure,resulting in the precipitation of metastable δ-polymorph.XPS results showed that as the sodium stearate content increased,its proportion on the particle surface also increased.This was mainly due to the surface activity and larger molecular size of sodium stearate,causing it to aggregate on the particle surface during drying.IGC results showed that adding sodium stearate increased the dispersive surface energy of the microparticles,but decreased their surface polarity.When the sodium stearate content was 10％w/w,the dispersive surface energy of the particles reached 65.1 mJ/m2,and the surface reaction energy measured using isopropanol as a probe was 11.42 kJ/mol.Moreover,the addition of sodium stearate disrupted the orderly arrangement of mannitol molecules on the particle surface,resulting in a more complex molecular arrangement.Accordingly,the surface roughness index measured with iso-octane as a probe decreased with increasing sodium stearate con-tent.The flowability of the samples improved significantly with higher sodium stearate content:the Carr's index of the spray-dried pure mannitol sample was as high as 48.56％,but decreased to 29.7％when the sodium stearate content was 10％w/w,which was due to the hydrophobic shell formed by sodium stearate enrichment on the particle surface. Conclusion The IGC technology provides new insights into the surface properties of spray-dried microparticles.The addition of sodium stearate promotes the formation of a hydrophobic surface on the spray-dried microparticles,enhances the dispersive sur-face forces,and reduces the surface reaction energy,making the sample less prone to absorbing water during collection,trans-fer,and storage,and ultimately improving their flowability.

Abstract:Objective When ultrasonic waves propagate through a liquid-solid suspension containing gas bubbles,significant acoustic scat-tering occurs at the gas-liquid interface due to the large acoustic impedance contrast,resulting in excess acoustic attenuation.This introduces errors in characterizing the particle size of solid particles based on the acoustic attenuation spectral analysis.The ultrasonic attenuation and inversion results are analyzed in a liquid-solid two-phase system by changing particle size and mixing ratio of micrometer bubbles,evaluating their influence on acoustic attenuation and the accuracy of particle size characterization for solid particles. Methods The acoustic scattering and absorption characteristics of solid elastic particles and bubbles were compared and ana-lyzed,with a focus on the resonance scattering properties of bubbles.Based on the theory of acoustic scattering and absorption in single solid elastic particles and bubbles,a Monte Carlo model for the solid particle-bubble hybrid system was developed.Numerical analysis was conducted on the ultrasonic attenuation of bubbles with different sizes and mixing ratios in monodisperse and polydisperse aqueous suspensions of micron-sized glass beads to evaluate their effect on the acoustic attenuation spectra.Furthermore,by comparing the accuracy of particle size inversion using the differential evolution algorithm,genetic algorithm,and particle swarm optimization algorithm,the particle swarm algorithm was selected to investigate the deviation in particle size inversion caused by the presence of bubbles. Results and Discussion As the bubble mixing ratio increased,the decay curve of the mixed particle system gradually shifted upward,with the root mean square error of the mixed particle system reaching up to 16.42.According to the particle size inver-sion results,in a monodisperse system where the bubbles and glass bead radius were 60 μm,the error was about 0.4％at a mix-ing ratio of 0.1％,around 1％at 0.3％,and about 6％at 1％.In the polydisperse system,a higher bubble mixing ratio led to an increase in the inverted particle size and a broader distribution width.For the ultrasonic frequency range of 1～10 MHz,micron-sized bubbles(＞10 μm)were located at the right side of the resonance scattering region.As the bubble size and ultrasonic fre-quency decreased(gradually approaching the resonance scattering region),the effect of bubbles on acoustic attenuation and par-ticle size characterization of solid particles became more significant.When the radius of both bubble and glass bead was 60 μm,the inversion error remained around 0.4％at a 0.1％mixing ratio.However,for bubbles with a 30 μm radius,the error increased to about 2％at the same mixing ratio.At a radius of 10 μm,bubbles with a 0.1％mixing ratio caused an inversion error of nearly 15％. Conclusion This study establishes a Monte Carlo model for a gas-liquid-solid three-phase mixed particle system and evaluates the effect of micro-bubbles on acoustic attenuation spectra and particle size characterization.The findings indicate that as the bubble mixing ratio increases,the errors in ultrasound attenuation and particle size characterization also increase.Moreover,resonance scattering significantly amplifies the errors when the bubble sizes approach the resonance scattering region.These results provide a theoretical basis for evaluating and mitigating bubble interference in particle measurement experiments.

Abstract:Objective Previous studies have explored the mechanical response mechanisms of elongated flexible particles under uniaxial compression,shear,and mixing,using both experimental and simulation methods.However,research on elongated flexible par-ticles with different arrangements and woven forms remains limited.To address this gap,the study explores the compressive strength of such particles with different arrangements and woven forms through triaxial compression simulations. Methods Compared to traditional models,such as spherical chains,elliptical chains,and rod chains,the sphero-cylinder model can more effectively simulate the deformation behavior and mechanical properties of elongated flexible particles of differ-ent materials.Therefore,triaxial compression simulations were used to investigate the mechanics of these particles connected by sphero-cylinder elements under different arrangements and woven forms. Results and Discussion Compared to vertically and horizontally arranged elongated flexible particles,randomly arranged ones generated higher bond forces and bond bending moments,leading to increased normalized deviatoric stress and solid volume frac-tion in the granular bed.Increasing the bond elastic modulus(Eb)enhanced the bond force and normalized deviatoric stress of vertically arranged particles at initial axial strains,though its effect diminished at larger strains.For randomly arranged par-ticles,higher Eb significantly elevated both the internal bond forces and inter-particle contact forces,further increasing the nor-malized deviatoric stress of the bed.However,horizontally arranged particles showed negligible changes in contact force and stress.Additionally,increasing the aspect ratio of randomly arranged particles or weaving them into a net structure greatly improved bond forces and inter-particle contact forces,resulting in higher normalized deviatoric stress and solid volume fraction of the granular bed. Conclusion During triaxial compression,the overall mechanical strength of granular beds with elongated flexible particles is sig-nificantly impacted by particle arrangements and woven forms.The sensitivity of elongated flexible particles to Eb varies across different particle arrangements.Eb more markedly impacts the strength of the granular bed with randomly arranged elongated flexible particles,whereas the strength of granular beds with vertically and horizontally arranged particles is less affected.Granu-lar beds with randomly arranged and woven elongated flexible particles exhibit superior overall strength enhancement compared to horizontal and vertical arrangements or non-woven forms.

Abstract:Objective The complex gas-solid flow in fluidized beds often leads to operational failures such as particle agglomeration,distri-bution plate clogging,gas short-circuiting,and hydrodynamic instability,jeopardizing production safety and economic benefits.Compared to the machine learning(ML)methods,manual monitoring and signal processing in traditional approaches have limi-tations in signal extraction and multi-type fault differentiation.This study evaluates the feasibility of ML methods for state identi-fication and fault diagnosis in gas-solid fluidized beds,benchmarking and optimizing typical ML models using the built-in AI model of DTEmpower.The research results provide insights into the development of artificial intelligence-based stabilization techniques for industrial fluidized bed systems. Methods A small cylindrical bubbling bed cold mold was constructed with transparent glass walls to visualize flow dynamics.The flow characteristics of fluid catalytic cracking(FCC)particles under normal working conditions,particle agglomeration(10％～50％by volume),and distribution plate blockage(12.5％～62.5％by area)were simulated.Transient pressure pulsa-tion signals were collected,and bed eigenvalues were calculated based on pressure sensor data.For fault diagnosis,four ML models,k-nearest neighbors(KNN),random forest(RF),support vector regression(SVR),and radius nearest neighbor(RNN),as well as the AI-agent of DTEmpower,were selected based on their characteristics and model features.Five types of models were constructed and their model performance was validated and compared. Results and Discussion As particle agglomeration worsened,the bed pressure drop and density decreased steadily,while the distribution plate pressure drop fluctuated,showing an overall downward trend.Distribution plate clogging increased plate pres-sure drop but decreased bed pressure drop and density.The trend variations could be used to determine the operational status of fluidized beds.An experienced operator could identify simple faults from trend data but not complicated faults.To achieve accu-rate identification of fault category and severity under conditions of particle agglomeration and distribution plate blockage,ML methods should be used.For known fault severities(limited domain),the AI-agent model and KNN achieved the highest accu-racy(88.89％),followed by RF(88.67％)and SVR(19.44％).For unknown fault severities(unqualified domain),RF had the highest accuracy(100％),followed by AI-agent(95.84％),SVR(87.5％),and RNN(87.5％).Overall,the KNN model demonstrated superior accuracy(93.75％)and differentiation rate(81.25％),while the AI-agent also excelled in fault diagno-sis under comparison. Conclusion This study offers insights into the development of AI-based technologies in operational stability solutions for indus-trial fluidized bed systems.Through a comprehensive comparison of five mainstream ML models,the optimal model for condition monitoring and fault diagnosis in fluidized beds was identified.The proposed method can distinguish the differences between par-ticle agglomeration and distribution plate blockage while quantitatively assessing failure severity,significantly enhancing opera-tional safety.It provides a foundation for industrial-scale state identification and fault diagnosis systems based on actual indus-trial data.However,it should be noted that this study was conducted at a laboratory scale with simplified operating conditions and limited parameter variations.Future work should focus on applying these methods to industrial-scale applications.Histori-cal DCS data should be employed,and specific reaction conditions and mechanisms should be considered,which will require specialized model adjustments.

Abstract:Objective Pleated filter cartridge is internationally recognized as an efficient dust removal device.It can be classified into two forms:circular and rectangular flat pleated filter cartridges.Compared to circular cartridges,the rectangular flat pleated filter cartridges have the advantages of a smaller size and higher efficiency,resulting in excellent filtering performance.However,due to their intricate pleated structure,the surface pressure distribution of the rectangular flat pleated filter cartridge is uneven,lead-ing to insufficient dust removal.Based on a newly designed intensive injection nozzle,the pressure intensity and uniformity are analyzed. Methods In this paper,a new type of intensive injection nozzle was designed based on the pleated and compact structure of the rectangular flat pleated filter cartridge.A pulse-jet experiment platform was used to explore the pressure distribution at different injection pressures and distances.The optimal injection parameters for intensive injection nozzles were selected by comparing them with traditional circular injection nozzles.Finally,the industrial powder coating experiments were used to test the cleaning effect of the intensive injection nozzles in actual industrial operations.The experiment results demonstrated the effectiveness of these nozzles in improving pressure distribution uniformity. Results and Discussion It was found that when the injection distance increased,the peak pressure on the sidewall of the two types of injection nozzles showed a decreasing trend.However,with intensive injection nozzles,the maximum sidewall pressure exceeded 600 Pa,meeting the pressure required for pulse cleaning.In contrast,when using traditional circular injection nozzles,the peak pressure occurred at the positive injection test point,with the highest value reaching 5 600 Pa and the lowest at only 342 Pa,failing to meet the pressure criteria for dust cleaning.The maximum pressure difference of the circular nozzle reached 1 952 Pa,showing significant fluctuations.In comparison,the maximum pressure difference of the intensive injection nozzle was only 1 092 Pa,with a much gentler decline.Increasing the injection pressure could enhance the pressure intensity to a certain extent,but the difference in uniformity became more apparent.With the use of intensive injection nozzle,the unifor-mity of pressure distribution on the filter cartridge surface improved by 17.67％compared to previous research results.Compre-hensive analysis showed that the optimal cleaning effect could be obtained when the injection pressure was 0.2 MPa,and the injection distance was 20 mm.Industrial powder coating experiments showed that as the filtration wind velocity increased,tradi-tional circular injection nozzles tended to experience system failures.When the filtration wind velocity was 1.0 m/min,the dif-ference in dust residue between the two types of injection nozzles was 0.748 kg,with a maximum dust residue increase differ-ence of 21.81％,further validating the effectiveness of the intensive injection nozzles.With the intensive injection nozzle,the maximum operating resistance difference could be maintained at 285 Pa,and the residual dust content was less than 2％of the feed amount.Changes in dust concentration had little effect on system operation.Industrial conditions could be adjusted accord-ing to specific production and application scenarios to optimize the performance of rectangular flat pleated filter cartridge dust collectors. Conclusion Intensive injection nozzles can effectively enhance the overall pressure distribution uniformity on the surface of rect-angular flat pleated filter cartridge,improve cleaning performance,and enable the dust collector system to maintain stable long-term operation.

Abstract:Significance High-entropy alloys(HEAs)are mainly prepared using traditional melting and casting methods,which often result in issues such as severe component segregation,coarse microstructures,and internal shrinkage defects.These limitations and constraints on size and shape hinder their broader engineering applications.However,with the rapid development of science and technology,advanced near-net-shape forming technologies,such as 3D printing and powder metallurgy,have been gradu-ally applied to HEA powder preparation.In recent years,HEA powders have gained significant attention as raw materials for the preparation of bulk components,coatings,films,and other functional materials.Despite this growing interest,comprehensive studies on HEA powders,especially nano-sized powders,remain rare.To enhance our understanding of HEA powders,this paper comprehensively examines their preparation processes,curing methods,and functional applications,providing a refer-ence for future development and theoretical research on HEA powder preparation. Progress This review systematically summarizes recent advancements in HEA powder preparation techniques,including mechanical alloying(MA),gas atomization,plasma rotating electrode atomization,carbothermal shock(CTS),pyrolysis,elec-tric shock,scanning probe lithography,plasma arc,DC arc evaporation,and chemical reduction.Each method is evaluated for its advantages and limitations.The solidification processes of HEA powders,such as sintering,coating,and additive manufac-turing,are discussed.The functional applications of HEA powders are also investigated,including hydrogen storage,medical and bioengineering,catalysts,and electromagnetic shielding.For instance,their excellent mechanical properties and biocom-patibility make them ideal for orthopedic implants and dental treatment materials.In environmental and energy applications,HEA powders can be efficient catalysts.They can also be used as electromagnetic shielding materials such as electromagnetic shielding wall panels and electromagnetic isolation rooms. Conclusions and Prospects Although significant achievements have been made in the design and preparation of HEA powders,considerable challenges remain.MA and atomization are currently the main methods for preparing HEA powders,but further improvements in efficiency and powder quality are needed.Future research should focus on addressing fundamental issues in powder preparation and developing innovative preparation methods.Their structural stability,mechanical properties,and func-tional performance in energy storage,magnetism,and catalysis need to be further studied.Additive manufacturing,with its abil-ity to create unique dislocation structures and microstructures,holds great potential in developing high-performance HEA materi-als.Through material genetic engineering,high-throughput powder metallurgy techniques can accelerate the screening of HEA components,shortening the development cycle of alloys.In addition,the flexibility of powder metallurgy enables the design of heterogeneous HEA materials such as composite,layered,and gradient structures,which have potential applications in aero-space,biomedical engineering,and other fields,promoting further development of HEA technologies.

Abstract:Significance High-power piezoelectric devices,operating under harsh conditions such as high voltage and large currents,have attracted significant scientific and technological interest in recent years.The main component of high-power devices is piezoelectric ceramics.However,these ceramics face significant challenges during operation.For instance,domain switching under alternating electric fields generates intense mechanical vibrations,which can lead to cracks in piezoelectric ceramics due to their low tensile strength.Additionally,significant thermal dissipation occurs due to electrical and mechanical losses,leading to a temperature rise in the components.This combination of mechanical stress and thermal effects severely degrades the electri-cal performance and service life of piezoelectric devices.To address these challenges,developing piezoelectric ceramics with a high electromechanical coupling coefficient,a large piezoelectric coefficient,a high quality factor,an elevated Curie tempera-ture,and low dielectric loss is essential for the practical application and advancement of high-power piezoelectric devices. Progress The electromechanical coupling coefficient,piezoelectric coefficient,quality factor,Curie temperature,thermal sta-bility,dielectric constant,and dielectric loss are key performance parameters for high-power piezoelectric ceramics.In this paper,the effects of element doping,component design,and preparation technology on the electrical properties of piezoelectric ceramics are systematically analyzed.Element doping plays a crucial role in optimizing piezoelectric performance.Donor dop-ing,for example,improves the electromechanical coupling coefficient,piezoelectric coefficient,and dielectric constant.How-ever,it also increases dielectric loss and significantly reduces the quality factor.In contrast,acceptor doping has the opposite effect,reducing dielectric loss and improving the quality factor but often at the expense of other electrical properties.To address these trade-offs,co-doping with both donors and acceptors has emerged as a promising strategy in recent years to achieve a more balanced improvement in overall electrical properties.Advancements in preparation technology have further expanded the poten-tial of high-power piezoelectric ceramics.Advanced fabrication techniques,such as sintering aids,optimization of sintering atmospheres,texturing processes,and refined sintering methods,have significantly enhanced the properties of piezoelectric ceramics.In this study,lead-based(including PbZrTiO3-based and BiScO3-PbTiO3-based)and lead-free(including BiFeO3-BaTiO3-based and(K,Na)NbO3-based)piezoelectric ceramic systems for high-power piezoelectric devices are reviewed.The latest studies on element doping,component design,and preparation techniques for these systems are systematically summa-rized,providing insights into their development for high-power piezoelectric devices. Conclusions and Prospects With the extensive application of high-power devices such as ultrasonic transducers,piezoelectric transformers,ceramic filters,and piezoelectric ultrasonic motors in military and high-tech fields,high-power and high-perform-ance piezoelectric ceramics have shown significant commercial market potential.At the same time,higher demands are being placed on the quality factor(Qm value),loss characteristics,and properties of piezoelectric ceramics.High-power piezoelectric ceramics face two major challenges.First,there is often a trade-off relationship between the mechanical quality factor(Qm),piezoelectric coefficient(d33),electromechanical coupling coefficient(kp),and Curie temperature(tc),making it difficult to enhance them simultaneously.Second,the temperature stability of piezoelectric properties in practical applications requires urgent improvement.To address these challenges,researchers have focused on two primary strategies:regulating phase struc-tures through doping and employing advanced fabrication techniques,such as texturing.These approaches are effective in enhancing their overall performance and play a crucial role in developing high-power lead-free piezoelectric ceramics.It is con-cluded that composition design and process optimization are critical elements for designing high-power piezoelectric ceramics.

Abstract:Significance Cyclone separators,known for their simple structure,ease of installation and operation,and cost-effectiveness,are considered one of the most economical gas-solid separation devices and are widely utilized in industries such as energy,chemical engineering,environmental protection,and pharmaceuticals.By utilizing the high-speed rotation of airflow to generate centrifugal force,cyclone separators achieve efficient gas-solid separation.However,despite meeting basic requirements,chal-lenges including low separation efficiency,significant pressure drop,and issues such as cyclone tube blockage,scaling,and abrasion persist.Increasing demands for energy efficiency and emission reduction have raised expectations for cyclone separa-tors,necessitating improvements in efficiency,pressure drop,and stability.Although extensive efforts have been made to explore separation mechanisms and enhance separation performance,further technical innovation and application optimization are needed to address these issues. Progress Based on the inlet flow direction,cyclone separators are classified into tangential inlet and axial inlet with guide vanes.Researchers worldwide have conducted extensive experimental and numerical simulation studies to enhance their separa-tion efficiency,including analyzing unconventional vortex flow fields,improving internal structures,and integrating external auxiliary devices.However,the complex movement of solid-phase particles inside the separators poses challenges for perfor-mance optimization.To overcome the drawbacks in traditional experimental methods such as long experimental cycles and high workload,numerical simulation techniques,including large eddy simulation(LES),Reynolds stress models,and enhanced RNG k-ε models,are increasingly used to analyze flow behavior and assess the separator performance under different operating conditions.Two main indicators,i.e.,pressure drop and separation efficiency,are used to evaluate their performance.Pres-sure drop estimates the energy loss experienced by cyclone separators under specific operating conditions,while separation effi-ciency evaluates their ability to separate particles.Key sensitive factors influencing separation performance include operational and structural parameters.Operational parameters consist of inlet particle concentration,particle size,inlet velocity,and inlet pressure,which can alter the internal flow field of separators.Structural parameters include cone-to-cylinder ratio,diameter,and height.Despite the relatively simple structure,determining the optimal combination of these structural parameters remains a challenge.In scenarios requiring high processing volumes and superior separation performance,such as in chemical plants and pharmaceutical factories,multi-stage separation processes can enhance processing capacity and separation efficiency.How-ever,cyclone separators are not optimal for separating fine particles,and further optimization is required to meet the increasing demands for separation performance. Conclusions and Prospects Cyclone separator technology has garnered significant attention from scholars worldwide,with extensive research focusing on improving separation performance and structural design.However,advances in numerical simula-tion techniques and computational capabilities present opportunities for further model and algorithm optimization,which could enhance simulation accuracy and efficiency.Moreover,exploring more complex operating conditions through numerical simula-tions and conducting comparative analyses between simulation results and actual operational data can deepen our understanding of the internal flow behavior of cyclone separators,facilitating their practical applications in engineering.Challenges persist in improving their separation efficiency,particularly for extremely fine particles and highly diverse particle distributions.Fluctua-tions in particle loading,changes in gas composition,and variations in operating conditions can further compromise the stability and reliability of the device.High pressure drop,leading to increased operational costs and limited applications,remains a cru-cial challenge.Future research should focus on refining design and optimization strategies to meet the complex gas-solid separa-tion requirements across different industrial applications.The integration of technologies such as 3D printing,big data,and arti-ficial intelligence offer promising pathways to explore new research methods,further deepening our understanding of the internal flow fields and separation processes of cyclone separators under complex conditions,and promoting their broader application in practical engineering.

Abstract:Significance Metal 3D printing,as a cutting-edge additive manufacturing(AM)technique,has exhibited great potential in its applications in aerospace,medical,automotive,and other high-tech industries,providing an efficient and flexible approach for metal component production.To comprehensively understandits development trendsand industrial applications,this paper reviews current research on metal 3D printing powders,focusing on powder preparation methods. Progress The printing quality and performance of metal 3D formed parts are significantly influenced by the metal powders' defects and characteristics,including particle size,sphericity,bulk density,flowability,and purity.Particle size affects powder reactivity and flowability,with different manufacturing processes requiring specific sizes.Powders with high sphericity exhibit better flowability and produce components with higher forming quality.Bulk density and flowability are affected by particle shape,size distribution,and surface condition,with higher bulk density promoting the formation of continuous melt pools during printing.Purity is equally important,as high-purity powders reduce the impact of impurities on performance,especially with strict control over oxygen content.Tapped density also affects the density and mechanical properties of printed parts.Despite advances in manufacturing,metal powders still have typical defects that compromise printing quality.Hollow spheres formwhen voids develop within metal droplets,reducing the density and mechanical properties of printed parts.Satellite particles occur when smaller particles adhere to larger ones,affecting powder flowability and forming quality.Poor sphericity of powders,due to irregular particle shapes,leads to uneven powder distribution and reduces mechanical properties.Non-uniform particle size distribution increases porosity and reduces fatigue life.To improve printing quality,various powder preparation methods for metal 3D printing are employed,mainly including gas atomization,water atomization,ultrasonic atomization,centrifugal atomi-zation,plasma atomization,and plasma spheroidization.These techniques are suitable for different application scenarios and material systems.Gas atomization uses high-pressure inert gases to atomize liquid metal,which is cost-effective and highly effi-cient but requires optimization of powder sphericity and particle size distribution.Water atomization enables fast cooling but results in higher oxygen content,affecting the performance of final printed parts.Ultrasonic atomization employs high-frequency vibrations to produce highly spherical droplets with uniform size distribution.Centrifugal atomization prepares metal powders through high-speed rotation,suitable for producing powders of larger particle sizes.Plasma atomization meltswire using high-temperature plasma,producing powders with high sphericity,purity,and low oxygen content.Plasma spheroidization trans-forms irregular particles into spherical ones using high temperature and surface tension effects,significantly improving powder quality.Despite progress,challenges remain in producing fine powders with narrow size distributions while maintaining low oxy-gen content.Further development is needed to enhance powder quality consistency and process stability. Conclusions and Prospects Metal 3D printing technology,with its unique advantages,has revolutionized manufacturing indus-try.Its mature printing methods and advanced metal powder systems enable the manufacturing of high-precision and high-strength components.As the technology continues to evolve through technological innovation and process optimization,future developments should focus on cost control and accuracy improvement.The integration of emerging technologies,such as artifi-cial intelligence and machine learning,is driving significant advancements in powder production processes and material cost reduction.These developments are accelerating the transition toward more intelligent and automated production processes.Moreover,powder preparation methods are progressing toward more efficient,environmentally sustainable,and economically viable solutions.The improvements in cost-effectiveness and quality of final products broaden their applications and adoption in more fields,enabling customized production of special parts with complex shapes.

Abstract:Objective The scanning surface inspection system(SSIS)for wafer surface is an essential tool for quality control in semiconduc-tor manufacturing processes,and its performance evaluation requires calibration using standard wafer(SW)materials.To achieve independent calibration,there is an urgent need for China to develop SW materials that meet calibration requirements.This will address the low domestic production rate of SSIS equipment and further advance the research and application of wafer standard materials in China. Methods In this paper,a generation-deposition system for SW preparation was developed.The system utilized a differential mobility classifier(DMC)to screen polystyrene aerosols of the desired particle size and a scanning mobility particle sizer(SMPS)to analyze particle size distribution.Through theoretical and experimental analysis,the physical parameters of the depo-sition chamber were optimized and validated through numerical simulations in Ansys Fluent.Moreover,the influence of opera-tional parameters on uniform deposition and deposition efficiency was investigated. Results and Discussion When the particle size ranged from 100 to 300 nm,uniform physical parameters of the deposition cham-ber could achieve similar deposition results.However,for particles with sizes between 40 and 70 nm,different combinations of deposition chamber parameters were required.Deposition uniformity was influenced by the relative rotation position.Under the same conditions,particle size monodispersity was negatively correlated with the flow-to-time ratio.Increasing the deposition time improved deposition efficiency but had no impact on particle size monodispersity.Thermophoretic effect improved deposi-tion efficiency but caused contamination,rendering the contaminated SW unsuitable for SSIS calibration.Rotation increased the deposition spot area by 26％and decreased the concentration by 10％,reducing deposition efficiency but facilitating better con-trol of deposition time and improving distribution uniformity.Differences in particle size distribution between SSIS and SMPS were observed due to their distinct calibration principles. Conclusion Based on the simulation and experimental results,a 2-inch wafer standard with 200 nm polystyrene particles was successfully prepared,meeting the calibration requirements.The wafer standard materials prepared using this generation-deposition system have traceable particle sizes and a quantity distribution that meets the calibration requirements of the SSIS.

Abstract:Objective Among various clean energy sources,nuclear energy is one of the most widely used and technologically advanced options,offering significant advantages such as high energy density,large output power,environmental cleanliness,and eco-nomic efficiency.However,nuclear power generation releases energy from atomic nuclei through nuclear fission,inevitably pro-ducing radioactive pollutants.Radioactive iodine isotopes(such as 129I and 131I)are typical gaseous radionuclides that readily dif-fuse in the air,causing serious pollution to the atmosphere,water systems,and ecosystems.Therefore,the safe and effective capture of radioactive iodine is a significant concern.Recently,porous materials have been utilized to adsorb iodine vapor due to their excellent adsorption properties,achieving promising results.Compared to traditional inorganic porous materials(e.g.,activated carbon,zeolites),porous organic polymers(POP)offer advantages such as low density,high physical and chemical stability,large specific surface area,excellent adsorption performance,and good recyclability,making them suitable for radio-active iodine capture. Methods In this study,three novel POP,i.e.,PA-POP-A,PA-POP-B,and PA-POP-C,were prepared using petroleum asphalt(PA)as the raw material and three different crosslinking agents,1,4-bis(chloromethyl)benzene,4,4'-bis(chloro-methyl)biphenyl,and 9,10-bis(chloromethyl)anthracene.The materials were prepared using a fast and efficient ball-milling method.The reagents and catalyst were loaded into a 250 mL zirconia grinding jar with 50 zirconia spheres(10 mm diameter)under an argon atmosphere.The planetary high-energy ball mill was operated at 400 r/min for 2 hours at room temperature.After milling,100 mL of anhydrous methanol was added to quench the reaction.Subsequently,the mixture was filtered using a Buchner funnel,washed repeatedly with methanol and chloroform,and then dried under vacuum at 60 ℃ for 24 hours,yielding three dark brown powder products.For iodine adsorption experiments,0.20 g of each porous material was accurately weighed and placed into a pre-weighed cylindrical sample bottle.Then,2.0 g of solid iodine was added to an identical sample bottle.Both sample bottles were placed in a sealed 250 mL glass container and then heated in a 75 ℃ drying oven to simulate a satu-rated iodine vapor environment.At fixed time intervals(1,2,3,4,5,6,8,12,16,20,and 24 hours),samples were removed,cooled down,and weighed to calculate iodine uptake.Each iodine adsorption experiment was conducted in triplicate to evaluate reproducibility and experimental error. Results and Discussion Under mechanical ball-milling conditions,the raw materials underwent Friedel-Crafts alkylation reac-tion to form porous polymers with stable chemical structures and well-developed pore channels,as confirmed by Fourier trans-form infrared spectroscopy(FTIR),solid-state nuclear magnetic resonance(NMR),and N2 adsorption characterization.The specific surface areas of PA-POP-A,PA-POP-B,and PA-POP-C were 1 048,1 700,and 843 m2/g,respectively.N2 adsorption-desorption isotherms indicated that all three porous materials contained abundant micropores(＜2 nm),mesopores(2-50 nm),and a small amount of macropores.Iodine adsorption reached equilibrium after 8 hours,with maximum mass uptakes of 623％,652％,and 582％for PA-POP-A,PA-POP-B,and PA-POP-C,respectively.After 5 adsorption-desorption experiments,only slight decreases in iodine uptake were observed.After 10 days of storage at room temperature and atmospheric pressure,the residual iodine contents were 568％,612％,and 510％,respectively,indicating excellent retention performance and minimal iodine loss. Conclusion In this study,three novel organic porous materials(PA-POP-A,PA-POP-B,and PA-POP-C)were prepared using low-cost PA as the raw material through a simple and feasible mechanical ball-milling method.The resulting materials exhibit high specific surface areas and abundant microporous structures,with excellent iodine vapor adsorption and retention per-formance.After multiple reuse cycles and prolonged exposure under ambient conditions,the materials maintained high adsorp-tion capacity with minimal iodine loss.This preparation method offers notable advantages such as high efficiency,operational simplicity,and feasibility,as well as low energy and organic solvent consumption.These features provide significant benefits in energy conservation and environmental sustainability,demonstrating potential for large-scale industrial applications.